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Staking the Head???

markctr3

Senior Member
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Three reasons I'm rebuilding my TR3 engine AGAIN. 1)dirt in the bearings (my fault) 2)Cracked crank (not my fault) 3)blown head gasket (the reason for this post). On kazkastner.com there was a page sample that talked about milling the head, and consequently blowing out the head gasket between 2 and 3. Then he listed (partially) how to fix the problem. Has anyone done this, or even heard about this? I REALLY don't want to rebuild this motor again.
 
I know what it is and it might work with a solid copper gasket. A properly surfaced head and block should not need this.

It is not a fix for a warped head or block. Or if there is a problem with your cyl liner installations. Your head torque procedure might also lead to this problem. Also I can not see it working with a standard gasket.
 
Hi,

Staking is done to heavily milled TR race heads to prevent the thinned head collapsing into the cooling passages.

With the head removed, you should be able to very easily tell if there is any problemwith it. Lay it face up and put a straight edge across the head to see if there is any warpage and look closely for any damage or collapse of the sealing surfaces right around where the rim of each cylinder, where it contacts the head.

The original TR 4-cyl. heads are nice and strong, until they're milled a good deal to significantly increase compression. TR2/3 heads need a little more work to be milled as much as later heads can be, but the primary trouble area with the earlier head is interference between the water pump and the thermostat neck. Still, the earlier heads cannot be milled as much as the later ones, because there isn't as much metal cast around the compression area.

However, unless you have .120"+ milled off and 11:1 or higher compression going on (do you need to run 100+ octane racing fuel?), staking is unlikely to be needed or helpful.

With a street engine that's been milled less (say .030 to .090") and is under 10:1 CR approx., I think it's far more likely that there's a problem with the cylinder liners not standing above the face of the block enough. There should be .003 to .005" protrusion to effect a good seal with the gasket... and this is adjusted by using thicker or thinner figure 8 gaskets under the sleeves, or by skimming the end of the cyl. sleeve or skimming the top of the block slightly, depending upon whether more or less protrusion is needed.

By the way, while it's off the block is a good time to measure the head and estimate how much it's been milled, if you aren't certain. Originally, I think it should have been 3.30" thick (someone correct me if I'm wrong... this number might be 3.330"), from the sealing face to the top flange. Get some good measurements at various places around the edges to compare with this number and try to determine about how much your car's head has been milled, if at all.

Yes, as mentioned, another good possibility is improper torque. Old stretched or thread-damaged head studs or nuts are often the culprit, causing improper torque by giving a false impression that enough torque has been applied (when the threads bind). Also flares or belling on the threaded stud holes in the top the block can hold the head off from making a good seal, in spite of "proper" torquing.

I hope this helps. Keep us posted what you find.

/ubbthreads/images/graemlins/cheers.gif
 
Unfortunately, I don't know how much was milled on the head. I told the machine shop to give me 10:1 compression based on the bore and stroke of the new liners and pistons. I also installed new ARP head bolts -- and virtually everything else on the engine. I did a 3-step torque sequence and used the copper-sandwich head gasket.

Since I'm not a mechanic by trade (let alone a British mechanic) I am forced to ask people like you that have done this sort of stuff before. After stumbling over the "Staking the Head" article (while trying to find out out how to time a D-grind cam) I thought, this is exactly what happened to me. I am going to have to get Kas' book to find out more about this since I was only able to read a sample of the first page.
 
staking the head,
even if it measures ok when it is on the bench (flat etc), it may still be required. go to jack & tony drews site and talk to jack. he has a current pattern he uses. i would suggest you do it (sorry alan) with 10:1. each casting is different and could be thin. even though your compression is reasonable, the cam you have could give very high pressures at lower rpms (4000), it depends on the cam. make sure the block and liner projections are even ie +- .0005. make sure the head gasket does not protrude into the combustion chamber, ie 87mm liner needs 88mm hole in gasket including clearance around intake valve if you have beveled the liner in this area.i understand jack has a new headgasket, copper with a steel fire ring.when you assemble your head,put the spray gasket sealer on, place head in position on top, do not torque up!let stand till next day, then torque up.
Rob
 
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